Itaipu Lake (Lago de Itaipu) is a lake on the Brazil-Paraguay border, artificially formed in 1982 on the Paraná River with the closing of the gates of the Itaipu Hydroelectric Dam detour channel.
It covers an area of 1,350 km2 (520 sq mi), 770 km2 (300 sq mi) on the Brazilian side and 580 km2 (220 sq mi) on the Paraguayan side. It also includes 66 small islands, 44 of which are on the Brazilian side and 22 on the Paraguayan side of the border.
